1. Field of the Invention
The present invention relates to an optical device cavity structure, an optical device and a method for manufacturing an optical device cavity structure.
2. Description of the Background Art
Optical semiconductor devices are known in the prior art. An optical semiconductor device is, for example, a CCD module provided in a video camera, a digital camera, a digital still camera, etc., and typically includes an optical device and a wiring substrate. An optical device includes an optical element chip, a light-transmitting member and a first terminal section. With the first terminal section being electrically connected to the wiring substrate, the optical device can emit light from the optical element chip or receive light coming through the light-transmitting member.
In addition to optical semiconductor devices, other types of semiconductor devices include semiconductor devices for high frequencies. For example, Japanese Laid-Open Patent Publication No. 2001-332656 discloses a high-frequency signal amplifier device and a method for manufacturing the same. The publication discloses a method for manufacturing a high-frequency signal amplifier device as follows. First, a dielectric layer with a plurality of metal patterns formed on the surface thereof is used as at least one of a plurality of dielectric layers, and a dielectric multi-layer substrate having a structure as follows is used. The dielectric multi-layer substrate has a structure such that when proceeding in the depth direction from anywhere within a predetermined area of one substrate surface of the dielectric multi-layer substrate, a plurality of metal patterns or a metal surface provided at a deeper position than the plurality of metal patterns will be reached before reaching the other substrate surface of the dielectric multi-layer substrate. Then, the predetermined area of the dielectric multi-layer substrate is irradiated with laser light. This removes the dielectric layer from a portion extending in the depth direction from one substrate surface to the plurality of metal patterns or the metal surface, thus exposing the plurality of metal patterns and the metal surface in the predetermined area. Then, a semiconductor element is placed in the predetermined area. Thus, a high-frequency signal is input to the semiconductor element via some of the plurality of metal patterns, and an amplified high-frequency signal is output from the semiconductor element via some other metal patterns. It is stated that with such a manufacturing method, as opposed to those in which a semiconductor device is manufactured while forming an isolation trench in advance, it is not necessary to account for a manufacturing margin, and it is possible to realize a reduction in size in the manufactured high-frequency signal amplifier device while compensating for the insufficient isolation.
Typically, in a semiconductor device for high frequencies, the semiconductor element chip is sealed with a resin. On the other hand, an optical component such as a light-transmitting member or a lens barrel is often placed on an optical semiconductor device. Therefore, the structure of an optical semiconductor device and that of a semiconductor device for high frequencies are quite different from each other. Therefore, if one attempts to manufacture an optical semiconductor device using the dielectric multi-layer substrate disclosed in Japanese Laid-Open Patent Publication No. 2001-332656, it is necessary to devise measures for placing an optical component on the dielectric multi-layer substrate.